Securing an extrusion press ram to a thrust member

ABSTRACT

It is known to retain a conical shoulder on the rear end of an extrusion press ram to a thrust member such as a cross-head by means of a retaining ring which has a conical recess in its rear face corresponding to a ram shoulder, the retaining ring being tightened towards the thrust member in some suitable manner. I now provide a generally square rear end on the ram shoulder and give the retaining member a generally square opening for receiving the ram shoulder, so that the ram can be secured to the thrust member by inserting the rear end portion of the shoulder through the opening and turning the ram through about 45* before tightening the retaining member towards the thrust member.

United States Patent 1 Robra 3,732,716 May 15, 1973 SECURING AN EXTRUSION PRESS RAM TO A THRUST MEMBER [75] Inventor: Helmut Robra, Mulheim/Ruhr,

Germany [73] Assignee: Schloemann Aktiengesellschaft, Dusseldorf, Germany [22] Filed: Feb. 19, 1971 [21] App]. No.: 116,878

[30] Foreign Application Priority Data Feb. 20, 1970 Germany... ..P 70 06 133.5

[52] US. Cl ..72/273, 72/481 [51] Int. Cl ..B2 lc 25/00 [58] Field of Search ..72/273, 481, 462, 72/264 [56] References Cited UNITED STATES PATENTS 3,411,337 11/1968 Murphy ..72/273 1,720,592 7/1929 Fitzgerald 72/481 Primary Examiner-Charles W. Lanham Assistant Examiner-R. M. Rogers A trorney- Holman and Stern [57] ABSTRACT It is known to retain a conical shoulder on the rear end of an extrusion press ram to a thrust member such as a cross-head by means of a retaining ring which has a conical recess in its rear face corresponding to a ram shoulder, the retaining. ring being tightened towards 11 Claims, 2 Drawing Figures PATENTEDMY15I975 3.732.716

INVENTOR HEL MUT ROBRA- fi h o SECURING AN EXTRUSION PRESS RAM TO A TIIRUST MEMBER The invention relates to securing an extrusion press ram to a thrust member (such as a moving cross-head) for thrusting the ram in an extrusion press, particularly in an extrusion press for metals. A separate pressure plate may lie between the ram and the thrust member. In a prior arrangement, the ram rear end portion has a conical shoulder and can be pressed by means of a retaining ring which has a conical recess in its rear against the pressure plate. The thrust member can have an abutment arrangement on its side nearest the billet container of the extrusion press.

In a known rapid attachment system (German Pat. No. 949,558), the ram is provided with a splined base which engages in a corresponding aperture in a bayonet ring. The bayonet ring itself is secured on the thrust member by means of a securing ring which is externally threaded. The ram is attached to the thrust member by turning the bayonet ring so that the splines are correspondingly positioned (i.e., so that land engages land) and then pressing the rear end of the ram on to the thrust member by means of the threading on the securing or retaining ring.

The disadvantages of this arrangement are, firstly that there is little possibility of re-machining the rear end or base of the ram; secondly that shaping of the ram rear end or base and bayonet ring is complicated;

and thirdly that the ram (which is inserted while cold) very easily jams or binds when heated to working tern: perature as a result it becomes impossible or at best difficult to release the ram by rotating the retaining ring (having external threading) since the threading prevents the ring expanding. In addition, the arrangement is expensive, involving as it does a number of components.

It is an object of the invention to provide a means for securing the ram which is free from theaforementioned disadvantages and can easily be released from the thrust member when heated, even if the ram becomes jammed in the container of the extrusion press and the thrust member abutment arrangement abuts the container.

The present invention provides an arrangement for securing an extrusion press ram to a thrust member (tag, a moving cross-head) for thrusting the ram in an extrusion press, wherein the ram rear end portion has a shoulder with a generally polygonal rear end and a retaining member (e.g., a ring) for securing the shoulder to the thrust member has a generally polygonal opening for receiving the shoulder, the retaining member being so shaped that to secure the ram to the thrust member, at least the rear end portion of the ram shoulder is inserted through the opening, relative rotary movement is effected between the ram and the retaining member to bring the polygonal end of the shoulder substantially out of register with the polygonalopening, and the retaining member is tightened up. Retaining surfaces on the retaining member, between'the corners of the polygun, will abut retaining surfaces on the shoulder adjacent the corners of the polygon. The invention extends to an extrusion press having the arrangement of the invention, and to an extrusion press ram having a shoulder with a polygonal end for co-operation with the retaining member of the arrangement of the invention.

The shoulder is preferably generally conical with polygonal flats, the retaining member being of complementary shape. The polygon is preferably a square, whereby a relative rotary movement through about 45 can be effected between the ram and the retaining member before the retaining member is tightened up. The advantage of the polygon having a relatively small number of sides, such as a square, is that sufficiently large retaining surfaces can be provided without a great risk of the ram jamming when it is heated to working temperature. It is a general advantage of the polygonal shape over say a spline shape that the risk of jamming can be lessened.

The retaining member is preferably received in a recess in the thrust member and is centered by engagement between its external periphery and the sides of the recess. The retaining member may be secured to the thrust member by threaded studs and nuts. Compression springs may be inserted between the retaining member and the thrust member, for biasing the retaining member and thrust member apart.

The thrust member may have abutment members on its side nearest the ram head (i.e., the side facing the position of the billet container of the extrusion press), in order to abut say the container and prevent further forward movement of the thrust member and ram. There are preferably gaps between adjacent abutment members; it is thus possible to insert a spanner through these gaps to loosen the nuts which hold the retaining member on the thrust member when the abutment members abut directly against the container of the extrusion press. Preferably, the inwardly-facing sides of the abutment members are straight and form a polygon with gaps at the corners corresponding to the gaps be tween adjacent abutment members.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which FIG. I is a plan view of the cross-head of an extrusion press with a retaining ring for securing the ram (part of the retaining ring being shown broken away); and,

FIG. 2 is an axial longitudinal section through the mandrel mounting system, along the line II-II of FIG. 1 on an enlarged scale relative to that of FIG. 1.

.A cylinder cross-head l is connected by means of traction columns 2 with a counter platen not shown in the drawing. A thrust member in the form of a moving cross-head 4 is connected to a plunger 3 and has supports 5 sliding on a slideway 6. A pressure plate 7'is inserted into one side of the cross-head 4 and the base rear end portion 9 of a ram 8 is secured by means of a retaining member comprising a circular retaining ring 10. The retaining ring 10 has its periphery centered by the cross-head 4 and is held on the moving cross-head 4 by four stay bolts 11 and nuts 12. The retaining ring 10 has a square aperture 13 with radiused corners. The rear of the retaining ring 10 (i.e.z the side facing the pressure plate 7) has a part-conical recess with a half angle. of less than 45 and a diameter at the rear face equal to the diagonal of the square, (i.e.: the retaining ring is shaped by machining a conical recess into itsrear side). The base 9 of the ram is square and has a conical shoulder 14 which fits into the conical rear recess in the retaining ring 10. The cone serves to center the ram 8 in the retaining ring 10 and thus relative to the-center of the press.

The retaining ring bears against the pressure plate 7 and cross-head 4 by way of compression springs located in blind holes 16 in the retaining ring 10. Thus the retaining ring 10 is pressed outward from the pressure plate 7 when the nuts 12 on the stay bolts 11 are released, releasing the base 9 of the ram. Once the ram 8 has been rotated through 45 about its longitudinal axis, it may be withdrawn from the square aperture 13. To ensure that the base 9 of the ram cannot be rotated through more than 45 in the square aperture, stop pins 17 are provided in the pressure plate 7.

The base 9 of the ram 8 is inserted into the square aperture 13 in the retaining ring 10 with the nuts 12 released. When the ram 8 has been rotated through 45 and hits the stop pins 17, the four nuts 12 are tightened. This locks the projections of the mandrel base 9 behind the sides of the square aperture 13.

The cross-head 4 has four straight-sided abutment members 19 on its side facing the billet container 18 which members 19 form a square with a gap 20 left between each of the abutment members 19. The gaps 20 are for the insert-ion of a spanner, if necessary, to release the nuts 12 and hence the ram 8 when the abutment members are abutting directly against the container 18.

1 claim:

1. An extrusion press comprising a container for receiving a billet to be extruded,

a ram for extruding the billet, the ram having a shoulder on its rear end portion, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square,

a thrust member for thrusting the ram,

a retaining member securing the ram to the thrust member, the retaining member defining a generally square opening receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough,

means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45 between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram,

and means for applying thrust to the thrust member to thrust the ram and extrude the billet.

2. An extrusion press as claimed in claim 1, wherein said ram shoulder is generally conical and has flats forming said square, and the retaining member having a partially'conical face for engaging the conical surface of the shoulder.

3. An extrusion press as claimed in claim 1, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.

4. An extrusion press as claimed in claim 2, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.

5. An extrusion press as claimed in claim 1, wherein said means for tightening the ram towards the thrust member comprise threaded studs secured to said thrust member and nuts on the threaded studs.

6. An extrusion press as claimed in claim 5, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.

7. An extrusion press as claimed in claim 4, wherein said means for tightening the ram towards the thrust member comprises threaded studs secured to said thrust member and nuts on the threaded studs.

8. An extrusion press comprising a container for receiving a billet to be extruded,

a ram for extruding the billet, the ram having a shoulder on its rear end portion, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square,

a thrust member for thrusting the ram,

a retaining member securing the ram to the thrust member, the retaining member defining a generally square opening receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough,

means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45 between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram,

and means for applying thrust to the thrust member to thrust the ram and extrude the billet,

and comprising abutment members on the side of said thrust member facing said container, the abutment members defining gaps between adjacent abutment members, and the inwardly facing sides of the abutment members being straight and forming a polygonal with gaps at the corners thereof corresponding to said gaps between adjacent abutment members.

9. In an extrusion press having a container for receiving a billet to be extruded, a ram for extruding the billet, a thrust member for thrusting the ram and means for applying thrust to the thrust member to thrust the ram and extrude the billet, an arrangement for securing the ram to the thrust member, the ram having a shoulder on its rear end portion, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square, said arrangement comprising a retaining member for securing the ram to the thrust member, the retaining member defining a generally square opening for receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening for abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough, and means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45 between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram.

10. An extrusion press as claimed in claim 8, wherein said ram shoulder is generally conical and has flats forming said square, and the retaining member having a partially conical face for engaging the conical surface of the shoulder.

11. An extrusion press as claimed in claim 10, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member, said means for tightening the ram towards the thrust member comprising threaded studs secured to said thrust member and nuts on the threaded studs. 

1. An extrusion press comprising a container for receiving a billet to be extruded, a ram for extruding the billet, the ram having a shoulder on its rear end portion, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square, a thrust member for thrusting the ram, a retaining member securing the ram to the thrust member, the retaining member defining a generally square opening receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough, means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45* between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram, and means for applying thrust to the thrust member to thrust the ram and extrude the billet.
 2. An extrusion press as claimed in claim 1, wherein said ram shoulder is generally conical and has flats forming said square, and the retaining member having a partially-conical face for engaging the conical surface of the shoulder.
 3. An extrusion press as claimed in claim 1, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.
 4. An extrusion press as claimed in claim 2, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.
 5. An extrusion press as claimed in claim 1, wherein said means for tightening the ram towards the thrust member comprise threaded studs secured to said thrust member and nuts on the threaded studs.
 6. An extrusion press as claimed in claim 5, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member.
 7. An extrusion press as claimed in claim 4, wherein said means for tightening the ram towards the thrust member comprises threaded studs secured to said thrust member and nuts on the threaded studs.
 8. An extrusion press comprising a container for receiving a billet to be extruded, a ram for extruding the billet, the ram having a shoulder on its rear end portioN, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square, a thrust member for thrusting the ram, a retaining member securing the ram to the thrust member, the retaining member defining a generally square opening receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough, means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45* between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram, and means for applying thrust to the thrust member to thrust the ram and extrude the billet, and comprising abutment members on the side of said thrust member facing said container, the abutment members defining gaps between adjacent abutment members, and the inwardly facing sides of the abutment members being straight and forming a polygonal with gaps at the corners thereof corresponding to said gaps between adjacent abutment members.
 9. In an extrusion press having a container for receiving a billet to be extruded, a ram for extruding the billet, a thrust member for thrusting the ram and means for applying thrust to the thrust member to thrust the ram and extrude the billet, an arrangement for securing the ram to the thrust member, the ram having a shoulder on its rear end portion, the shoulder having a generally square rear end and defining retaining surfaces adjacent the corners of said square, said arrangement comprising a retaining member for securing the ram to the thrust member, the retaining member defining a generally square opening for receiving the ram shoulder and defining retaining surfaces between the corners of said generally square opening for abutting said retaining surfaces on the ram shoulder, said generally square opening being large enough for said generally square rear end of the ram shoulder to pass therethrough, and means for tightening the retaining member towards the thrust member, whereby the ram is secured to the thrust member by inserting at least the rear end portion of the ram shoulder through said generally square opening, effecting a relative rotary movement through about 45* between the ram and retaining member, and tightening the retaining member towards the thrust member to engage corresponding said retaining surfaces and secure the ram.
 10. An extrusion press as claimed in claim 8, wherein said ram shoulder is generally conical and has flats forming said square, and the retaining member having a partially conical face for engaging the conical surface of the shoulder.
 11. An extrusion press as claimed in claim 10, wherein said thrust member defines a recess receiving said retaining member and engaging the external periphery of said retaining member, thereby centering said retaining member, said means for tightening the ram towards the thrust member comprising threaded studs secured to said thrust member and nuts on the threaded studs. 